1. Field of the Invention
The present invention relates to a cylinder liner for internal combustion engines. In particular, the invention relates to a cylinder liner that has a rough exterior surface that is formed during the casting process, the surface having spines of different shape and structure to facilitate adherence of the liner to the engine block.
2. The Prior Art
In combustion engines having an engine block made of a cast iron alloy or an aluminum alloy, cylinder liners are usually inserted into the cylinder bores of the engine block. The liners consist of cylindrical pipe sections and their inner surfaces define the combustion space of the combustion chamber of the engine. The outer surfaces are often treated to give the outer surface a roughened texture. This rough texture ensures adhesion of the cylinder liner to the engine block when the liner is cast into the engine block.
Some cylinder liners, such as the one shown in U.S. Pat. No. 7,171,935 to Komai, have been treated so that the exterior surface of the liner has a series of spines extending out from the liner. Other liners, such as U.S. Pat. No. 7,665,440 to Holtan et al. describe grit-blasting the outer surface of the cylinder liner so that the outer surface has cavities throughout. German Patent No. DE102009043566A1 to Bischofberger et al. describes a cylinder liner that is created with a textured surface that can have grooves, ribs, shafts, studs, mushrooms, thorns or a combination thereof. This texture can be created by removing material from the liner or by a coating.
U.S. Pat. No. 8,402,881 to Sato et al. discloses an insert casting structure having a rough-cast surface with spines of specific diameters. Based on the measurements, it can be determined that the spines have a more or less cylindrical shape.